1. Field of the Invention
The present invention relates to camera drive devices and, more particularly, to a drive device used in operating an objective lens, a shutter sector, aperture blades or the like
2. Description of the Prior Art
In recent years, the camera-drive devices have been broadly utilized to rotate a rotor magnetized with multiple poles by energizing a single coil wound around a stator, because of no requirement for mechanical charge mechanisms. Particularly, such drive devices are effective together with the requirement of size reduction of the drive device as the cameras are made more compact. FIG. 6 shows a conventional drive device, wherein a rotor R radially magnetized with a multiplicity of poles arranged at a location sandwiched between opposite ends S1, S2 of a stator S is rotated around a center axis 22 by energizing a coil L wound around the stator. By the rotation of the rotor R, a sector lever 20 provided on a common axis to the rotor R is structurally operated to operate sectors 23, 24 through a pin 20a provided on the sector lever 20, thereby opening and closing the shutter aperture 2. That is, the rotor R, the stator S and the coil L are arranged on the common plane, which occupies around the shutter aperture 2 a planar area of schematically shown at an angle xcex8 in the figure.
However, the conventional drive device if arranged nearby a camera lens barrel needs much planar space because of the arrangement on the common plane of the stator, coil and rotor, resulting in a problem with difficulty in reducing the size of the drive device.
In order to solve the above problem, the present invention is provided with yokes formed by extension portions extending in the radial direction of the rotor and rise-bent portions vertically rise-bent from both ends of the extension portions to reach the stator magnetic pole plates, thereby enabling spatial arrangement for the camera drive device.
A structure is provided such that a motor for driving a camera operating member is structured by a permanent magnet rotor magnetized in a radial direction, a stator for driving the rotor and a coil for exciting the stator; the stator being formed by a pair of stator magnetic plates opposed in a radial direction to the rotor and yokes partly wound around by the coil and for inducing a magnetic flux on the coil to both of the stator magnetic pole plates; and the yokes being formed by extension portions extending in the radial direction of the rotor in a position axially opposed to the rotor and rise-bent portions vertically rise-bent from both ends of the extension portions to reach the stator magnetic pole plates.
Also, the both stator magnetic pole plates may be made in a one body structure through magnetically-separated narrowed portions. Also, the coil may be wound around on the rise-bent portion or the extension portion.
FIG. 1 is an explanatory view of one embodiment of the present invention;
FIG. 2 is a block diagram showing a camera control system used in the embodiment of the invention;
FIG. 3 is a fragmentary view of the one embodiment of the invention;
FIG. 4 is a fragmentary view of another embodiment of the invention;
FIG. 5 is a fragmentary view of another embodiment of the invention;
FIG. 6 is a plane view of a conventional example.